Remove unnecessary copy while decoding and constructing string

Signed-off-by: Bogdan Drutu <[email protected]>

.chloggen/rm-unncessary-copy-enhance.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: textutil
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Remove unnecessary copy while decoding and constructing string
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [37734]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: This PR affects all log receivers, text extension and kafkareceiver.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

.chloggen/rm-unncessary-copy.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: deprecation
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: pkg/stanza
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Deprecate all functions in stanza/decode
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [37734]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

extension/encoding/textencodingextension/config.go

@@ -20,9 +20,7 @@ func (c *Config) Validate() error {
 			return err
 		}
 	}
-	encCfg := textutils.NewEncodingConfig()
-	encCfg.Encoding = c.Encoding
-	_, err := encCfg.Build()
+	_, err := textutils.LookupEncoding(c.Encoding)
 	if err != nil {
 		return err
 	}

extension/encoding/textencodingextension/extension.go

@@ -32,14 +32,12 @@ func (e *textExtension) MarshalLogs(ld plog.Logs) ([]byte, error) {
 }
 
 func (e *textExtension) Start(_ context.Context, _ component.Host) error {
-	encCfg := textutils.NewEncodingConfig()
-	encCfg.Encoding = e.config.Encoding
-	enc, err := encCfg.Build()
+	enc, err := textutils.LookupEncoding(e.config.Encoding)
 	if err != nil {
 		return err
 	}
 	e.textEncoder = &textLogCodec{
-		enc: &enc,
+		decoder: enc.NewDecoder(),
 	}
 
 	return err

extension/encoding/textencodingextension/go.mod

@@ -13,6 +13,7 @@ require (
 	go.opentelemetry.io/collector/extension/extensiontest v0.119.0
 	go.opentelemetry.io/collector/pdata v1.25.0
 	go.uber.org/goleak v1.3.0
+	golang.org/x/text v0.22.0
 )
 
 require (
@@ -43,7 +44,6 @@ require (
 	go.uber.org/zap v1.27.0 // indirect
 	golang.org/x/net v0.33.0 // indirect
 	golang.org/x/sys v0.29.0 // indirect
-	golang.org/x/text v0.22.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20241202173237-19429a94021a // indirect
 	google.golang.org/grpc v1.70.0 // indirect
 	google.golang.org/protobuf v1.36.4 // indirect

extension/encoding/textencodingextension/text.go

@@ -11,12 +11,13 @@ import (
 
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/collector/pdata/plog"
+	"golang.org/x/text/encoding"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal/textutils"
 )
 
 type textLogCodec struct {
-	enc                   *textutils.Encoding
+	decoder               *encoding.Decoder
 	marshalingSeparator   string
 	unmarshalingSeparator *regexp.Regexp
 }
@@ -50,11 +51,11 @@ func (r *textLogCodec) UnmarshalLogs(buf []byte) (plog.Logs, error) {
 	for s.Scan() {
 		l := p.ResourceLogs().AppendEmpty().ScopeLogs().AppendEmpty().LogRecords().AppendEmpty()
 		l.SetObservedTimestamp(now)
-		decoded, err := r.enc.Decode(s.Bytes())
+		decoded, err := textutils.DecodeAsString(r.decoder, s.Bytes())
 		if err != nil {
 			return p, err
 		}
-		l.Body().SetStr(string(decoded))
+		l.Body().SetStr(decoded)
 	}
 
 	return p, nil

extension/encoding/textencodingextension/text_test.go

@@ -14,12 +14,10 @@ import (
 )
 
 func TestTextRoundtrip(t *testing.T) {
-	encCfg := textutils.NewEncodingConfig()
-	encCfg.Encoding = "utf8"
-	enc, err := encCfg.Build()
+	enc, err := textutils.LookupEncoding("utf8")
 	require.NoError(t, err)
 	r := regexp.MustCompile(`\r?\n`)
-	codec := &textLogCodec{enc: &enc, unmarshalingSeparator: r, marshalingSeparator: "\n"}
+	codec := &textLogCodec{decoder: enc.NewDecoder(), unmarshalingSeparator: r, marshalingSeparator: "\n"}
 	require.NoError(t, err)
 	ld, err := codec.UnmarshalLogs([]byte("foo\r\nbar\n"))
 	require.NoError(t, err)
@@ -30,12 +28,10 @@ func TestTextRoundtrip(t *testing.T) {
 }
 
 func TestTextRoundtripMissingNewline(t *testing.T) {
-	encCfg := textutils.NewEncodingConfig()
-	encCfg.Encoding = "utf8"
-	enc, err := encCfg.Build()
+	enc, err := textutils.LookupEncoding("utf8")
 	require.NoError(t, err)
 	r := regexp.MustCompile(`\r?\n`)
-	codec := &textLogCodec{enc: &enc, unmarshalingSeparator: r, marshalingSeparator: "\n"}
+	codec := &textLogCodec{decoder: enc.NewDecoder(), unmarshalingSeparator: r, marshalingSeparator: "\n"}
 	require.NoError(t, err)
 	ld, err := codec.UnmarshalLogs([]byte("foo\r\nbar"))
 	require.NoError(t, err)
@@ -46,11 +42,9 @@ func TestTextRoundtripMissingNewline(t *testing.T) {
 }
 
 func TestNoSeparator(t *testing.T) {
-	encCfg := textutils.NewEncodingConfig()
-	encCfg.Encoding = "utf8"
-	enc, err := encCfg.Build()
+	enc, err := textutils.LookupEncoding("utf8")
 	require.NoError(t, err)
-	codec := &textLogCodec{enc: &enc}
+	codec := &textLogCodec{decoder: enc.NewDecoder()}
 	require.NoError(t, err)
 	ld, err := codec.UnmarshalLogs([]byte("foo\r\nbar\n"))
 	require.NoError(t, err)

internal/coreinternal/textutils/encoding.go

@@ -4,64 +4,15 @@
 package textutils // import "github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal/textutils"
 
 import (
-	"errors"
 	"fmt"
 	"strings"
+	"unsafe"
 
 	"golang.org/x/text/encoding"
 	"golang.org/x/text/encoding/ianaindex"
 	"golang.org/x/text/encoding/unicode"
-	"golang.org/x/text/transform"
 )
 
-// NewEncodingConfig creates a new Encoding config
-func NewEncodingConfig() EncodingConfig {
-	return EncodingConfig{
-		Encoding: "utf-8",
-	}
-}
-
-// EncodingConfig is the configuration of a Encoding helper
-type EncodingConfig struct {
-	Encoding string `mapstructure:"encoding,omitempty"`
-}
-
-// Build will build an Encoding operator.
-func (c EncodingConfig) Build() (Encoding, error) {
-	enc, err := lookupEncoding(c.Encoding)
-	if err != nil {
-		return Encoding{}, err
-	}
-
-	return Encoding{
-		Encoding:     enc,
-		decodeBuffer: make([]byte, 1<<12),
-		decoder:      enc.NewDecoder(),
-	}, nil
-}
-
-type Encoding struct {
-	Encoding     encoding.Encoding
-	decoder      *encoding.Decoder
-	decodeBuffer []byte
-}
-
-// Decode converts the bytes in msgBuf to utf-8 from the configured encoding
-func (e *Encoding) Decode(msgBuf []byte) ([]byte, error) {
-	for {
-		e.decoder.Reset()
-		nDst, _, err := e.decoder.Transform(e.decodeBuffer, msgBuf, true)
-		if err == nil {
-			return e.decodeBuffer[:nDst], nil
-		}
-		if errors.Is(err, transform.ErrShortDst) {
-			e.decodeBuffer = make([]byte, len(e.decodeBuffer)*2)
-			continue
-		}
-		return nil, fmt.Errorf("transform encoding: %w", err)
-	}
-}
-
 var encodingOverrides = map[string]encoding.Encoding{
 	"utf-16":   unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM),
 	"utf16":    unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM),
@@ -73,8 +24,8 @@ var encodingOverrides = map[string]encoding.Encoding{
 	"":         unicode.UTF8,
 }
 
-func lookupEncoding(enc string) (encoding.Encoding, error) {
-	if e, ok := EncodingOverridesMap.Get(strings.ToLower(enc)); ok {
+func LookupEncoding(enc string) (encoding.Encoding, error) {
+	if e, ok := encodingOverrides[strings.ToLower(enc)]; ok {
 		return e, nil
 	}
 	e, err := ianaindex.IANA.Encoding(enc)
@@ -88,18 +39,25 @@ func lookupEncoding(enc string) (encoding.Encoding, error) {
 }
 
 func IsNop(enc string) bool {
-	e, err := lookupEncoding(enc)
+	e, err := LookupEncoding(enc)
 	if err != nil {
 		return false
 	}
 	return e == encoding.Nop
 }
 
-var EncodingOverridesMap = encodingOverridesMap{}
-
-type encodingOverridesMap struct{}
+// DecodeAsString converts the given encoded bytes using the given decoder. It returns the converted
+// bytes or nil, err if any error occurred.
+func DecodeAsString(decoder *encoding.Decoder, buf []byte) (string, error) {
+	dstBuf, err := decoder.Bytes(buf)
+	if err != nil {
+		return "", err
+	}
+	return UnsafeBytesAsString(dstBuf), nil
+}
 
-func (e *encodingOverridesMap) Get(key string) (encoding.Encoding, bool) {
-	v, ok := encodingOverrides[key]
-	return v, ok
+// UnsafeBytesAsString converts the byte array to string.
+// This function must be called iff the input buffer is not going to be re-used after.
+func UnsafeBytesAsString(buf []byte) string {
+	return unsafe.String(unsafe.SliceData(buf), len(buf))
 }

internal/coreinternal/textutils/encoding_test.go

@@ -12,6 +12,7 @@ import (
 	"golang.org/x/text/encoding/korean"
 	"golang.org/x/text/encoding/simplifiedchinese"
 	"golang.org/x/text/encoding/unicode"
+	"golang.org/x/text/transform"
 )
 
 func TestUTF8Encoding(t *testing.T) {
@@ -43,11 +44,45 @@ func TestUTF8Encoding(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			encCfg := NewEncodingConfig()
-			encCfg.Encoding = test.encodingName
-			enc, err := encCfg.Build()
+			enc, err := LookupEncoding(test.encodingName)
 			assert.NoError(t, err)
-			assert.Equal(t, test.encoding, enc.Encoding)
+			assert.Equal(t, test.encoding, enc)
+		})
+	}
+}
+
+func TestDecodeAsString(t *testing.T) {
+	tests := []struct {
+		name     string
+		decoder  *encoding.Decoder
+		input    []byte
+		expected string
+	}{
+		{
+			name:     "nil",
+			decoder:  &encoding.Decoder{Transformer: transform.Nop},
+			input:    nil,
+			expected: "",
+		},
+		{
+			name:     "empty",
+			decoder:  &encoding.Decoder{Transformer: transform.Nop},
+			input:    []byte{},
+			expected: "",
+		},
+		{
+			name:     "empty",
+			decoder:  &encoding.Decoder{Transformer: transform.Nop},
+			input:    []byte("test"),
+			expected: "test",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			enc, err := DecodeAsString(test.decoder, test.input)
+			assert.NoError(t, err)
+			assert.Equal(t, test.expected, enc)
 		})
 	}
 }

pkg/ottl/go.mod

@@ -24,7 +24,6 @@ require (
 	go.uber.org/zap v1.27.0
 	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
 	golang.org/x/net v0.34.0
-	golang.org/x/text v0.22.0
 )
 
 require (
@@ -50,6 +49,7 @@ require (
 	go.opentelemetry.io/otel/sdk/metric v1.34.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/sys v0.29.0 // indirect
+	golang.org/x/text v0.22.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20241202173237-19429a94021a // indirect
 	google.golang.org/grpc v1.70.0 // indirect
 	google.golang.org/protobuf v1.36.4 // indirect

pkg/ottl/ottlfuncs/func_decode.go

@@ -7,11 +7,8 @@ import (
 	"context"
 	"encoding/base64"
 	"fmt"
-	"strings"
 
 	"go.opentelemetry.io/collector/pdata/pcommon"
-	"golang.org/x/text/encoding"
-	"golang.org/x/text/encoding/ianaindex"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal/textutils"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/ottl"
@@ -71,7 +68,7 @@ func Decode[K any](target ottl.Getter[K], encoding string) (ottl.ExprFunc[K], er
 			}
 			return string(decodedBytes), nil
 		default:
-			e, err := getEncoding(encoding)
+			e, err := textutils.LookupEncoding(encoding)
 			if err != nil {
 				return nil, err
 			}
@@ -85,19 +82,3 @@ func Decode[K any](target ottl.Getter[K], encoding string) (ottl.ExprFunc[K], er
 		}
 	}, nil
 }
-
-func getEncoding(encoding string) (encoding.Encoding, error) {
-	if e, ok := textutils.EncodingOverridesMap.Get(strings.ToLower(encoding)); ok {
-		return e, nil
-	}
-	e, err := ianaindex.IANA.Encoding(encoding)
-	if err != nil {
-		return nil, fmt.Errorf("could not get encoding for %s: %w", encoding, err)
-	}
-	if e == nil {
-		// for some encodings a nil error and a nil encoding is returned, so we need to double check
-		// if the encoding is actually set here
-		return nil, fmt.Errorf("no decoder available for encoding: %s", encoding)
-	}
-	return e, nil
-}